Exhaust muffler with removable catalytic unit



May 20, 1969 D. G. THOMAS 3,445,196

EXHAUST MUFFLER WITH REMOVABLE CATALYTIC UNIT Filed June 6, 1966 Sheetof 2 D. G. THOMAS 3,445,196

EXHAUST MUFFLER WITH REMOVABLE CATALYTIC UNIT May 20, 1969 Sheet 2 of2Filed June 6, 1966 i/MQ aw EE/6W United States Patent 3,445,196 EXHAUSTMUFFLER WITH REMOVABLE CATALYTIC UNIT Dean G. Thomas, Stoughton, Wis.,assignor to Nelson Muffler Corporation, Stoughton, Wis., a corporationof Wisconsin Filed June 6, 1966, Ser. No. 555,409 Int. Cl. Ftlln 3/14US. Cl. 23-288 9 Claims This invention relates generally to exhaustmufilers for internal combustion engines and more particularly toexhaust mufflers of the catalytic type.

Exhaust mufliers have heretofore been arranged to promote a morecomplete combustion of the gases passing therethrough; and one commonconstruction for this type of muffler provides for passage of theexhaust gases through a chamber containing a bed of oxidation-promotingcatalyst in the form of pellets. It has been found that smokey exhausts,especially from diesel engines tend to poison and eventually clog thebed of catalyst, sometimes in as little as six thousand miles of usage.However, this inactivation of the catalyst can be frequently cured byblowing air over the surfaces of the pellets, preferably in conjunctionwith the application of heat. Nevertheless, such regeneration of thecatalyst pellets requires special fittings on the muffler or removal ofthe pellets from the mufller for processing; and such procedures haveproved to be both inconvenient and time-consuming.

Therefore, an important object of the present invention is to provide acatalytic exhaust muffler which is arranged for easy removal of catalystsubstantially as a single unit.

A more general object of the present invention is to provide a new andimproved exhaust mufller of the catalytic type.

These and other objects and features of the present invention willbecome more apparent from a consideration of the following descriptions.

An exhaust mufller in accord with the invention includes a mufller shelland a catalyst container mounted in the shell and having an access portopening outwardly of the shell. A baflie arrangement is situated in theshell to direct exhaust gases from an inlet through the catalystcontainer and to an exhaust outlet; and a catalytic unit is disposedinside the container. In compliance with the invention, the catalyticunit includes a catalytically active body and means for unitizing saidbody.

The invention, both as to its construction and its mode of operation,will be better understood by reference to the following disclosure anddrawings, forming a part thereof, wherein:

FIG. 1 is a central sectional view taken through an exhaust mufflerconstructed in compliance with the invention;

FIG. 2 is a somewhat enlarged view of the lower section of the exhaustmuffler of FIG. 1 showing removal of the catalyst unit;

FIG. 3 is a view similar to the showing of FIG. 1 but illustrating amodified embodiment of the invention;

FIG. 4 is an enlarged view of the catalytic unit used in the mufiler ofFIG. 3; and

FIG. 5 is an enlarged view taken substantially along the line 55 of FIG.4.

Referring now in detail to the drawing, specifically to FIGS. 1 and 2,an exhaust muffler of the catalytic type is indicated generally by thereference numeral 10. The mufller comprises a substantially hollowmuffler shell 12, a catalyst container 14, an internal bafliearrangement including baffle plates 16 and 18, a catalytic unit 20, andan external cover 22 for the catalyst container 14.

Structurally, the mufller shell 12 includes a generally tubular body 24whose ends are closed off by flanged caps 26 and 28. The body 24 and thecaps 26 and 28 are usefully fabricated from a suitable metal such assteel, in which case the caps may be secured in place by weldments, notshown. The shell 12 is fabricated to include an exhaust gas inlet and anexhaust gas outlet, the former being defined by an imperforate tube 30and the latter being defined by an elongated tube 32 fashioned with asuitable number of apertures 34 opening radially through the extremeinward end thereof. The bafile plates 16 and 18 are disposed medially ofthe shell 12 and, when fabricated from metal, are secured in place bymeans of weldments, not shown. To facilitate their mounting in the shell12, the baffle plates 16 and 18 have peripheral flanges 36.Additionally, the baffle plates 16 and 18 are employed in supporting thetubes 30 and 32 and an inwardly disposed, imperforate tube 38 mediallyof the end caps 26 and 28; and for this purpose, the baffle plates areprovided with flanged apertures 40. A similar flanged aperture 42 isfashioned in baflle plate 18 to support the internal end of the catalystcontainer 14. Other than the flanged openings which admit and tightlyengage the tubes 30, 32 and 38 and the catalyst container 14, the baflleplates 16 and 18 are imperforate whereby to cooperate in directingexhaust gases from the exhaust gas inlet defined by tube 30 through thecatalyst container 14- and to the exhaust gas outlet defined by tube 32as will be described in greater detail hereinafter.

In compliance with the features of the invention, the catalyst container14 is positioned and arranged to facilitate removal of the catalyticunit 20. Accordingly, the container 14 is fashioned with an access port44 which is exposed externally of the shell 12 opening outwardlytherefrom. The container 14 also includes a midportion 46 having acylindrical bore 48 and an inner end wall 50 which is perforated with acentral aperture 52 to leave a narrow annular shoulder 54 confrontingthe access port 44. The shoulder 54 serves as a position stop for thecatalyst unit 20; and in order to accommodate the proper flow of exhaustgases through the container 14, the midportion 46 is fashioned with apattern of radial apertures 56 adjacent the end cap 28.

In compliance with the invention, the cover 22 is easily mounted on andeasily removed from the external end of the container; and for thispurpose, the container is fashioned with an annular, bulged rib 58surrounding the access port 44 spaced inwardly from the defined edgesthereof. cooperatively, the cover 22 includes a skirt or flange 60 whichis fashioned with a radially inwardly opening groove 62 which matablyreceives the rib 58. Furthermore, the cover 22 is desirably fabricatedfrom a material having sufficient resilience to permit snapping of thecover over the external end of the catalyst container. It is recognizedthat other means of releasably mounting the cover on the catalystcontainer may be employed.

The catalytic unit 20- is arranged, in accordance with the features ofthe invention, to include a catalytically active body 64 and means forunitizing the catalytically active body. In the embodiment of FIGS. 1and 2, the catalytically active body includes a number of cylindricaldiscs 66 which are arranged in stacked relationship and which are unitedby rigid screens 68 and a resilient bracket '70, bracket 70 beingfastened to the inner surface of cover 22 in alignment with the axis ofthe stacked discs 66. The screens 68 are situated at opposite ends ofthe stacked discs 66 and are loosely positioned within the container 14.Relatively rigid screens are employed to minimize flexing thereof duringassembly, use and disassembly of the catalytic unit. The resilientbracket 70 includes laterally outwardly turned feet 72 which areconnected by a U-shaped element 74. The element 74 is selected to takesufl'icient length to urge the assembled screens 68 and discs 66resiliently against the abutment or stop defined by shoulder 54. Thus,the discs 66 are urged tightly against each other whereby to minimizeself-abrading action when the muffler I is exposed to vibration.Furthermore, the discs are resiliently confined so that mechanicalshocks imposed on the mufller do not present a substantial fracturehazard, the resiliency of bracket 70 serving to absorb certaincomponents of such mechanical shocks. Advantageously, the bracket '70 isfabricated from stainless steel in order to provide the desiredspringiness and heat resistance.

The discs 66 are fabricated in accordance with principles well known inthe art and usefully employ a suitable oxidizing catalyst coated on orotherwise supported by a suitable ceramic matrix.

In compliance with the features of the embodiment of FIGS. 1 and 2, thecatalyst container 14 is substantially axially aligned with the tube 36defining the exhaust gas inlet. The purpose of this arrangement will bemade apparent shortly.

Having thus described one embodiment of the invention, it will bevaluable now to describe how that embodiment operates. When the muflleris assembled in the manner shown in FIG. 1, it is ready for attachmentin a motor driven vehicle or other device incorporating an internalcombustion engine having an exhaust which it is desired to control. Theshell 12 will be supported in a suitable manner and the exposed end oftube 30 will be connected to the conduit carrying the exhaust gases. Inthe case of an automobile or other similar vehicle, tube 36 will beconnected to the exhaust pipe thereof. The tube 32, defining the exhaustgas outlet from the muffler will, of course, be left Open to theatmosphere, either directly or through an auxiliary conduit such as atailpipe. With the mufiler so connected, exhaust gases will enterthrough the tube 30; and because of the imperforate nature of the baifieplates 16 and 18 and the imperforate character of the sections of thetubes 38 and 32 disposed between the baffle plates, the exhaust gaseswill enter the catalyst container through the central aperture 52passing through the adjacent screen 68 and through the porous network ofthe catalyst discs 66. The treated gases will thence pass through thedownstream screen 68 and into the chamber of container 14 whichsurrounds the bracket 74. The exhaust gases will then pass through theapertures 56 into the space between baffle plate 13 and end plate 28.Since tube 38 defines the only opening from this latter chamber to theatmosphere, the exhaust gases will pass through the tube 38 and into thechamber between end plate 26 and baffle plate 116, thereupon enteringthe inner end of tube 32 and the openings 34- adjacent thereto.

When it is desired to remove the catalytic unit for replacement orrejuvenation, the exhaust pipe connection at tube 36 will be broken, thecover 22 removed from the exposed end of container 1 and a dowel 76 orother similar element poked through the tube 36, through the aperture 52and into removable engagement with the catalytic unit Ztl. As will beapparent from an inspection of FIG. 2, pressing on the dowel '76 servesto extrude the catalytic unit through the container 14 and eventuallyout of the access port 44. Thereafter, a new or a rejuvenated catalyticunit may be pushed through the access port 44, as by employ of thebracket 74 attached to cover 22, the cover replaced and the connectionat the external end of tube renewed.

While a particular embodiment of the invention has been thus far shownand described, it should be understood that the invention is not limitedthereto since many modifications may be made. Therefore and in order toenhance the understanding of the invention, a modified embodiment isshown in FIGS. 35. Since the embodiment of FIGS. 3-5 is similar in manyrespects to the embodiments of FIGS. 1 and 2, like numerals have beenused to designate like parts with the suflix letter a being employed todistinguish those elements associated with the embodiments of FIGS. 3-5.

The exhaust muffier 10a shown in FIGS. 35 is characterized by theelimination of the internal tube 38 and a concomitant rearrangement ofthe flow path through the mufller and particularly by arrangement of thecatalytic unit 20a to be removable without the use of an auxiliaryelement such as the dowel 76.

In order to achieve the described removal of the catalyst unit 20a, thescreens 68a are perforated with central apertures 78 and the discs 66aare fashioned with central apertures 80, as is shown in FIG. 4. Inaddition, a post 82 is situated in the aligned apertures 78 and 80, theinternal end of post 82 being riveted over or otherwise radiallyexpanded to form a head 34. Cooperatively, the resilient bracket 76a isapertured at 86 to pass the post 82 into adjacency with the cover 22a.At the latter location, the post 82 terminates in a crossbar 88, thefeet 72a. of bracket 70a being deflected to form semi-cylindricalgrooves )0 which fit over and position the crossbar 83. Desirably,either the crossbar 88 or the head 84 is removably secured to the post82 as by means of a screw 92 indicated in FIG. 4.

The desired flow path through the mufiler 10a is achieved by rearrangingthe internal bafile plates and by appropriately perforating the tubes30a. and 32a. Turning to FIG. 3, an imporforate baffle plate 94 issituated be tween perforated baflle plates 96 and 98. Furthermore, thetube 30:: is fashioned with radial apertures 10% between end plate 26aand the baffle plate 96. Correspondingly, the tube 32a is fashioned withradial holes 102 in the region between battle plate 98 and end plate28a. The bathe plates 94, 96 and 98 are provided with suitably flangedapertures for receiving and mounting the internal ends of tubes 30a and32a and catalyst container 14a.

The flow path which is thus defined through the muffler 10a begins withgases entering the tube 30a, a portion of these gases passing throughthe apertures 100 and the remaining portion through the internal end ofthe tube. Those gases which pass through the inner end of tube 30a entera chamber formed between the baffle plates 94 and 96 and pass throughthe apertures in plate 96 to rejoin that portion of the inlet gases thathad passed through the apertures 100. The flow proceeds through theinnermost screen 68a and through the porous catalyst 66a, subsequentlypassing through the apertures 56a. in container 14a to enter the chamberbetween end cap 28a and baffie plate 98. A portion of these gases enterthe tube 32a through the holes 102, and a remaining portion passesthrough the perforations in baffle plate 98 to enter the inner open endof tube 32a.

When it is desired to remove the catalytic unit 20a from the exhaustmufiier 10a, the cover 22a will be snapped off the exposed end ofcontainer 14a. The bracket 70a. and the crossbar 88 may then be graspedto permit pulling of the catalytic unit 20a out of the container 14a. Inthe course of this removal operation, the head 84 will abut theunderlying portions of the adjacent screen 68:: to insure extraction ofthe entire catalytic unit with the post 82. After the catalytic unit isremoved, the crossbar 88 will be rotated relative to the legs 72a of theresilient bracket to disengage the crossbar from the grooves and releasethe spring tension on the screens 68a and the catalyst discs 66a. Thecrossbar 88 will then be removed by extraction of the screw 92 forfacility in regenerating or replacing the catalyst discs and thesupporting screens 68a. Replacement of the catalytic unit 2041 willproceed by reversing the described steps.

The specific examples herein shown and described should be considered asbeing primarily illustrative. Various changes beyond those describedwill, no doubt, occur to those skilled in the art; and such changes areto be understood as forming a part of this invention insofar as theyfall within the spirit and scope of the appended claims.

The invention is claimed as follows:

1. An exhaust muffier comprising: a substantially hollow mufiler shellhaving an exhaust gas inlet and and exhaust gas outlet; a catalystcontainer mounted in said shell and having an access port openingoutwardly of said shell; baflie means in said shell positioned tocooperate in directing exhaust gases from said inlet, through saidcontainer, and to said outlet; a catalytic unit removably disposedinside said container, including a catalytically active body and meansfor unitizing said body; and cover means for said access port.

2. An exhaust mufiler according to claim 1 wherein said container has aninternal wall perforated with an aperture dimensioned to admit a pusherelement into expell-able relationship with said catalytic unit.

3. An exhaust muffler according to claim 2 wherein the access port ofsaid catalyst container is axially aligned with said aperture and withsaid exhaust gas inlet.

4. An exhaust mufller according to claim 1 wherein said baffie means isconnected to said container in supporting relationship therewith.

5. An exhaust mufller according to claim 1 wherein said unitizing meansincludes screens disposed at opposite ends of said catalytically activebody.

6. An exhaust mufller according to claim 5 wherein said unitizing meansfurther includes a post passing through said body and engaging at leastone of said screens.

7. An exhaust mufiler according to claim 1 wherein said catalyticallyactive body comprises a plurality of axially aligned discs and whereinsaid unitizing means comprises resilient means acting between said covermeans and said catalytically active body to bias said discs into firmengagement with each other.

8. An exhaust muffler according to claim 7 wherein said resilient meansis a spring bracket engaging said cover means.

9. An exhaust mufiler according to claim 1 wherein said unitizing meansincludes screens disposed at opposite ends of said catalytically activebody, a post passing through said body and engaging at least one of saidscreens, and resilient means acting between said cover means and saidcatalytically active body, and wherein said catalytically active bodycomprises a plurality of actively aligned discs biased into firmengagement with each other by resilient means, said post having acrossbar end adjacent said cover means and said resilient means havinglaterally extending feet fittably engaging said crossbar for retainingsaid crossbar against said cover means.

References Cited UNITED STATES PATENTS 1,929,659 10/ 1933 Trumble et a1.2,004,865 6/ 1935 Grison. 3,018,841 1/1962' Gerlich. 3,025,132 3/1962Innes. 3,094,394 6/ 1963 Innes et al. 3,109,510 11/1963 Phelan.

MORRIS O. WOLK, Primary Examiner.

M. D. BURNS, Assistant Examiner.

US. Cl. X.R.

1. AN EXHAUST MUFFLER COMPRISING: A SUBSTANTIALLY HOLLOW MUFFLER SHELLHAVING AN EXHAUST GAS INLET AND AND EXHAUST GAS OUTLET; A CATALYSTCONTAINER MONTED IN SAID SHELL AND HAVING AN ACCESS PORT OPENINGOUTWARDLY OF SAID SHELL; BAFFLE MEANS IN SAID SHELL POSITIONED TOCOOPERATE IN DIRECTING EXHAUST GASES FROM SAID INLET, THROUGH SAIDCONTAINER, AND TO SAID OUTLET; A CATALYTIC UNIT REMOVABLE DISPOSEDINSIDE SAID CONTAINER, INCLUDING A CATALYTICALLY ACTIVE BODY AND MEANFOR UNITIZING SAID BODY; AND COVER MEANS FOR SAID ACCESS PORT.